Constantine TV show releases extended teaser at Comic-Con

The upcoming series stars Matt Ryan as John Constantine, a dark magician who becomes a supernatural detective to defend humans from dark forces.

The upcoming series is based on DC Comics' Hellblazer series, published in 1988 and 2013.

Last month, Ryan said that the series will "do the comics justice", adding: "There's over 300 issues of the Hellblazer comic. There's just so much source material to glean from. I've read about 100 of them now, so I've got a way to go."

"We're trying to stay as close to the source material as possible," he added.